1. Field of the Invention
The present invention relates to a method of controlling semiconductor fabricating equipment. More particularly, the present invention relates to a method of controlling semiconductor fabricating equipment so that the individual wafers of a single lot can be processed individually by the equipment under conditions ideally suited for each wafer considering the product into which the wafer is to be made.
2. Description of the Related Art
Semiconductor devices are fabricated by the execution of numerous processes with an extremely high degree of precision. These precise processes are carried out by highly functional equipment arranged along a semiconductor fabricating line. The elaborate operations of the equipment are monitored by operators through a management system to enhance the operation efficiency of the equipment.
Referring to FIG. 1, a plurality of wafers are inserted into the slots of a cassette, respectively, to form a lot 10 of intermediate semiconductor device products. This lot is transported to semiconductor fabricating equipment 3 of a fabricating line. The operator monitors the operation of the equipment 3 through an operator interface personal computer (O/I PC) 2 that is on-line with the equipment 3. The equipment 3 is also connected on-line to a host computer 1 through an equipment server 4. The host computer 1 is on-line with the O/I PC 2.
The operator inputs basic fabricating data, e.g., the ID of the lot 10 to be processed in the equipment 3, into the host computer 1 through the O/I PC 2. Based on the inputted basic fabricating data, the host computer 1 searches its database for appropriate data by which the equipment 3 will be controlled to process the lot 10. The database, as shown in FIG. 2, comprises process step IDs and a process program IDs (PPIDs). The data selected from the database is used by the host computer 1 for calculating process condition control data. The process condition control data is issued to the equipment server 4 for controlling the equipment 3 to process all of the wafers of the lot the same way.
For example, once an operator inputs a wafer lot ID, e.g. `A`, into the host computer 1 via the O/I PC 2, the host computer 1 assigns a process step ID, e.g. `A0010` corresponding to the wafer lot ID specified by the operator. Based on the database (FIG. 2) stored in the host computer 1, the host computer 1 also tags the lot with the PPID `a` corresponding to the process step ID `A0010`. Then, the host computer 1 formulates the process condition data necessary to cause the equipment 3 to process the wafers of the lot according to the conditions associated with a PPID of `a`.
Thereafter, the operator checks the process condition data and inputs a process commencing command or a process terminating command. If the process condition data is acceptable and the process commencing command is inputted, the process condition data is downloaded into the equipment server 3. The wafers of the lot are removed from the slots of the cassette and are placed in a plurality of chambers of the processing equipment, and equivalent conditions are established in each of the chambers so that each of the wafers are processed similarly according to the PPID `a`.
Unfortunately, the host computer 1 of the conventional semiconductor device fabrication management system can only assign one process step ID and PPID to the lot of wafers. A single process step ID and PPID can not be used by the equipment server to control the processing equipment in a manner in which the wafers are processed differently according to certain needs of the production line.
Such a problem is especially disadvantageous when processing large scale wafers. Large scale wafers can produce a great variety of end products. However, the conventional semiconductor device fabrication management system does not allow for the possibility of processing the large scale wafers of a single lot differently from one another, and a variety of end products thus can not be made from a lot of large scale wafers using just the conventional semiconductor device fabrication management system.